98 research outputs found
Global analysis of uncapped mRNA changes under drought stress and microRNA-dependent endonucleolytic cleavages in foxtail millet
GO functional enrichment analysis for different decay pattern mRNA. Gene Ontology (GO) analysis was performed for the type I, II, IV genes using WEGO which organizes information for cellular component categories, molecular function and biological process. The Pearson Chi-square test was used for statistical analysis. GO categories that show a significant (Îą =0.05) enrichment were analyzed and displayed here. (PDF 396Â kb
Mesoscopic-Functionalization of Silk Fibroin with Gold Nanoclusters Mediated by Keratin and Bioinspired Silk Synapse
2017年9月,厦门大学物理科学与技术学院刘向阳教授团队与河北大学闫小兵副教授团队合作, 在Small上发表此论文,第一次将功能化蚕丝用于制造阻变存储/神经元突触电子元件。这种蚕丝基生物仿生元器件, 可制成生物相容/可植入/可降解生物电子芯片, 在人工智领域以及生物医药方面,具有重要的应用前景。【Abstract】Silk fibroin (SF) offers great opportunities in manufacturing biocompatible/partially biodegradable devices with environmental benignity and biomedical applications. To obtain active SF devices of next generation, this work is to demonstrate a new functionalization strategy of the mesoscopic functionalization for soft materials. Unlike the atomic functionalization of solid materials, the meso-functionalization is to incorporate meso-dopants, i.e., functional molecules or nanomaterials, quantum dots, into the mesoscopic networks of soft materials. In this work, wool keratin (WK) molecules were adopted as mediating molecules to incorporate gold nanoclusters (AuNCs), into the mesoscopic networks of SF. It follows from our analyses that the β-crystallites between WK and SF molecules establish the binding between WK@AuNCs and the SF networks. The incorporated WK@AuNCs are electron rich and serve as electronically charged nano particles to bridge the growth of Ag filaments in bio-degradable WK@AuNCs–SF memristors. The meso-functionalization can greatly enhance the performance of SF materials and endows them with new functionalities. This can be highlighted by biocompatible/partly degradable WK@AuNCs functionalized SF resistive random-access memories, having the enhanced resistive switching memory performance, and the unique synapse characteristics and the capability of synapse learning compared with neat SF devices, and of great importance in nonvolatile memory, analog circuits, and neuromorphic applications.The work was supported by NUS tear 1 funding (WBS: R-144-000-367-112), the 111 Project (Grant No. B16029), National Natural Science Foundation of China (Grant Nos. 21404087 and 61674050, U1405226), Fujian Provincial Department of Science & Technology (Grant Nos. 2014H6022, 2015J05109), Natural Science Foundation of Guangdong Province (Grant No. 2015A030310007), 1000 Talents Program, and President Foundation from Xiamen University (Grant No. 20720160088), Ph. D. Programs Foundation of Ministry of Education of China (Grant No. 20130121110018). One of the authors, the primary affiliation of X.Y.L. is the Department of Physics, National University of Singapore. The authors are grateful to the China Scholarship Council (CSC) for the scholarship (Grant No. 201506630067) provided to one of the authors (Xing)
Global analysis of uncapped mRNA changes under drought stress and microRNA-dependent endonucleolytic cleavages in foxtail millet
Standard economic benefit evaluation of innovation-oriented enterprises——A case study of S enterprise
More and more innovation-oriented enterprises pay attention to standardization, but how much benefit standards can bring to the production and operation of enterprises is a matter of concern to managers. Therefore, it is of great significance to evaluate the impact of standards on the economic benefits of these enterprises. This paper takes S enterprise as an example to evaluate the impact of standards on its economic benefits
Study of Modeling and Optimal Take-Off Scheme for a Novel Tilt-Rotor UAV
The optimal trajectory planning for a novel tilt-rotor unmanned aerial vehicle (UAV) in different take-off schemes was studied. A novel tilt-rotor UAV that possesses characteristics of both tilt-rotors and a blended wing body is introduced. The aerodynamic modeling of the rotor based on blade element momentum theory (BEMT) is established. An analytical method for determining the taking-off envelope of tilt angle versus airspeed is presented. A novel takeoff–tilting scheme, namely tilting take-off (TTO), is developed, and its optimal trajectory is designed based on the direct collocation method. Parameters such as the rotor thrust, tilt angle of rotor and angle of attack are chosen as control variables, and the forward velocity, vertical velocity and altitude are selected as state variables. The time and the energy consumption are considered in the performance optimization indexes. The optimal trajectories of the TTO scheme and other conventional schemes including vertical take-off (VTO) and short take-off (STO) are compared and analyzed. Simulation results indicate that the TTO scheme consumes 47 percent less time and 75 percent less energy than the VTO scheme. Moreover, with minor differences in time and energy consumption compared to the STO scheme, but without the need for sliding distance, TTO is the optimal take-off scheme to satisfy the flight constraints of a novel tilt-rotor UAV
Thrust Vectoring Control of a Novel Tilt-Rotor UAV Based on Backstepping Sliding Model Method
In this paper, a control method of a novel tilt-rotor UAV with a blended wing body layout is studied. The novel UAV is capable of vertical take-off and landing and has strong stealth capabilities that can be applied to carrier-borne reconnaissance aircraft. However, the high aspect ratio of blended wing body UAVs leads to a wingtip or oar-tip touchdown problem when adopting the conventional position-attitude control (CPAC) scheme with a large crosswind disturbance. Moreover, when the UAV is subject to interference during reconnaissance, aerial photography, and landing missions, the conventional scheme cannot provide both attitude stability and track accuracy. First, a direct thrust vectoring control (DTVC) scheme is proposed. The control authority of the rotor tilt mechanism was added to enable the decoupling of the attitude and trajectory and to improve the response rate and response bandwidth of the flight trajectory. Second, considering the problems of strong couplings and parameter uncertainties and the nonlinear features and mismatched perturbations that are inevitable in the tilt-rotor, we designed a robust UAV controller based on the backstepping sliding mode control method and determined the stability of the control system through the Lyapunov function. Finally, in the case of crosswire interference during vertical takeoff and landing and the aerial photography missions of the UAV, the numerical simulation of the CPAC scheme and the DTVC scheme was carried out, respectively, and the Monte Carlo random test method was introduced to conduct the statistical test of the landing accuracy. The simulation results show that the DTVC scheme improves the landing accuracy and speed compared to the CAPC scheme and decouples the position control loop from the attitude control loop, finally enabling the UAV to complete the flight control in the VTOL phase
Genome-Wide Analysis of the Lysine Biosynthesis Pathway Network during Maize Seed Development.
Lysine is one of the most limiting essential amino acids for humans and livestock. The nutritional value of maize (Zea mays L.) is reduced by its poor lysine content. To better understand the lysine biosynthesis pathway in maize seed, we conducted a genome-wide analysis of the genes involved in lysine biosynthesis. We identified lysine biosynthesis pathway genes (LBPGs) and investigated whether a diaminopimelate pathway variant exists in maize. We analyzed two genes encoding the key enzyme dihydrodipicolinate synthase, and determined that they contribute differently to lysine synthesis during maize seed development. A coexpression network of LBPGs was constructed using RNA-sequencing data from 21 developmental stages of B73 maize seed. We found a large set of genes encoding ribosomal proteins, elongation factors and zein proteins that were coexpressed with LBPGs. The coexpressed genes were enriched in cellular metabolism terms and protein related terms. A phylogenetic analysis of the LBPGs from different plant species revealed different relationships. Additionally, six transcription factor (TF) families containing 13 TFs were identified as the Hub TFs of the LBPGs modules. Several expression quantitative trait loci of LBPGs were also identified. Our results should help to elucidate the lysine biosynthesis pathway network in maize seed
A DREB-Like Transcription Factor From Maize (Zea mays), ZmDREB4.1, Plays a Negative Role in Plant Growth and Development
The DREB (dehydration-responsive element binding)-type transcription factors are classified into six subgroups, named A-1 to A-6. The members of DREB A-1 and A-2 subgroups have been reported to be involved in response to various abiotic stresses. However, there were only a few genes belonging to A-3 to A-6 subgroups to be reported. In this study, we cloned a DREB A-4 subgroup gene from maize (Zea mays), ZmDREB4.1, and analyzed its characteristics and functions. ZmDREB4.1 was expressed in roots, stems, and leaves at very low levels. It was not induced by any biotic or abiotic treatment. ZmDREB4.1 was located in the nucleus, could directly bind to the DRE element and functioned as a transcriptional activator. The constitutive expression of ZmDREB4.1 in tobacco (Nicotiana tabacum L.) repressed leaf extension and hypocotyl, petiole and stem elongation. In maize, overexpression of ZmDREB4.1 repressed calli growth and regeneration. Further analysis showed that the smaller leaves of transgenic tobacco resulted from inhibition of cell division. The contents of cytokinin and auxin in transgenic leaves were severely decreased. The shorter hypocotyls, stems and petioles of transgenic tobacco were caused by inhibition of cell elongation. The transgenic hypocotyls, stems and petioles contained reduced gibberellin levels. Application of exogenous GA3 rescued the shorter hypocotyls, stems and petioles, but not the smaller leaves. These results demonstrated that ZmDREB4.1 plays an important role in the negative regulation of plant growth and development
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